Base support



FIG. 1 is a perspective view of a base support assembly;

FIG. 2 is a side elevation view, the opposing side being an identical mirror image;

FIG. 3 is a rear elevation view;

FIG. 4 is a front elevation view,;

FIG. 5 is a top plan view; and,

FIG. 6 is a bottom plan view.

The broken lines are for environmental purposes only and form no part of the claimed design. 

The ornamental design for a base support assembly, as shown and described. 